Astbonomical apparatus



(No Model.) 5 Sheets-Sheet 1.

J. DAVIS.

ASTRONOMIOAL APPARATUS. No. 291,698. Patented Jan. 8,- 1884.-

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(No Model.) 5 Sh etsSheet 2. I I

.J. DAVIS.

ASTRONOMIOAL APPARATUS.

No. 291,698. Patented Jan. 8, 1884.

(No Model.) 7 5 Sheets-Sheet 3.

J. DAVIS.

ASTRONOMIGAL APPARATUS. No. 291,698. PatentedJan. 8, 1884.

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(No Model) 5 Sheets-Sheet 4,

J. DAVIS.

ASTRONOMIGAL APPARATUS. No. 291,698. Patented Jan. 8, 1884.

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JOHX DAVIS, OF ALLEGHENY, PENNSYLY'ANIA.

AS'l'RCNOMICAL APPARATUS.

SPECIFICATION forming part of Letters Patent No. 291,698, dated January 8, 1884.

Application filed May 14, 1883.

(No model.)

To (all whom it may concern.-

Be it known that l, JOHN DAYIS, a citizen of the United States, residing at Allegheny, in the county of Allegheny and State of Pennsylvania, have invented certain new and useful Improvements in Astronomical Instruments,

' of which the following is a specification.

The object of my invention is, first, to con struct an instrument which shall, at any given period of the year, show the true relative positions of the sun, earth, and moon, the true direction and inclination of the earths axis, the proper positions of the lines of illumination and twilight, and the meridian and equatorial lines; second, to construct said instrument with the greatest possible simplicity of mechanism.

My invention consists in the hereinafter-dc scribed means for attaining said object.

In the drawings, Figure 1 represents a top view of my improved instrument; Fig. 2, a side elevation of same; Fig. 2, an elevationwith sun removed seen from the rear of the stand. Fig. 3 is a detail sectional view of the stand, the sun, a portion of the earth-carrying arm, and the operating mechanism. Fig. 3 is a top view of the stand. Fig. 4 is a detail sectional view of that portion of the earthbearing arm not shown in Fig. 3, and also of the earth and its operating mechanism. Fig. 5 is a longitudinal transverse seetionon line at x of Fig. 4-of the case bearing a portion of the operating mechanism of the earth and moon. Fig. 6 is a vertical section of the standcover.

Similar letters of reference indicate corresponding parts throughout the different views.

A represents the stand which carries the instrument, and which is provided with a platform, (0, upon which is secured a map (not shown) bearing the signs of the zodiac, graduations marked with the days and months, and such other signs as may be deemed desirable. Said stand is preferably constructed of cast metal, and is provided at its top with a circular flange, A, whose upper edge is divided into cogs, for the purpose hereinafter specified. About the top of the stand (said top being cylindrical in conformation) fits the cover A Said cover is provided with an. extension bearing upon the outer extremity a knob,- (6. About the center of its circul.ar )o1.'-

of the top of the stand is formed a circular or elliptical guide-channel, A Said channel is made eccentric to the center bolt, for the purpose hereinafter set forth.

B represents a cap which bears the standard B, the latter representing the sun. Said cap is secured to the sleeve a" by means of the thumb-screw Z), by which construction it will be seen that when the cover A" is revolved the sun 13 will maintain a fixed position rela tive to said cover. Upon one side of said standard B is a longitudinally-curved flange, 1), whose curvature is intended to represent the relative degree of curvature of the surface of the sun to that of the earth, (hereinafter described.) Through the middle of the standard or sun passes a rod, 13*, intended to represent a direct central ray of the sun, and above and below said rod are disposed pins 1)", representing other rays of the sun. To the extremity of said rod B is secured a crescent, b, representing a section of the plane of the ecliptic.

0 represents the earth-bearing arm, and is constructed with a longitudinal slot, 0, in its rear extremity, for the purpose about to be described. Said arm is a trilateral rectangle in cross-section, and is provided upon its lower edge with a teat or lug, G, which registers with the groove A" in the top of the stand. Said arm is adapted to work through a slot in the cover A and to slide within the extension of said cover. The aforesaid slot 0 allows the arm to slide in and out of the cover without interfering withthe bolt A. By this construction it will be seen that as the cover and is that said outer end of the earth-bearing arm I is made to describe an elliptical path corresponding with the elliptical orbit of the earth.

D represents the driving-shaft of the operiting mechanism, one end of said shaft revolving in a bearing extending downward from the inside of the top of the arm. Said shaft is provided near its aforesaid bearing with a long cog-pinion, D, whose teeth mesh with the cogs borne by the flange A. Theother extremity of said shaft is provided with a bearing in the outer end of the arm, as hereinafter described. will be seen that as the arm is revolved the pinion D, meshing with the toothed flange A, will cause the shaft D to revolve, and thereby impart motion to the hereinafter-described mechanism. The outer end of the arm 0 is expanded into a box or case, E, within which is contained a part of the operating mechanism.

Upon the outer end of the shaft D is a cogwheel, 1', (see Figs. 4 and 5,) which meshes with a pinion, f, supported on a shaft, f, provided with bearings secured to the side of the case E. Upon the body of said shaft is a worm, f, which meshes with a cog-wheel, f, borne by a shaft, F. Said shaft, at its upper part, is bent at an angle of about twenty-three and one-half degrees, and that portion of said shaft above the aforesaid bend forms the axis of the earth F. The lower end of said shaft is provided with a bearing in the bottom of the case E,while a second bearing is provided in the manner hereinafter described. It will thus be seen that as the arm 0 is revolved motion is imparted to the shaft D, and through the train of mechanism just described the shaft or axis F will be slowly revolved, and the inclination of axis of the earth changed to show the various seasons of the year.

Upon the shaft D, in rear of the aforesaid wheel f, is a crown-wheel, g,whose teeth gear with a cog-wheel, g, borne by the shaft 9*. Said shaft is provided with bearings in the top and bottom of the case E. The aforesaid wheel 9 meshes with the teeth of a wheel, made integral with a sleeve, 9. The latter extends upwardly some distance, and is provided with a crown-wheel, whose teeth mesh with those of an inclined crown-wheel, g, borne by. a sleeve, which surrounds the shaft F, and is screwed into the lower side (or south pole) of the earth. Said sleeve is prevented from slipping out of place by a shoulder (or collar) upon shaft F. By this construction it will be seen that as the arm 0 revolves, the sleeve g and with it the earth-through the medium of the mechanism just describedwill also revolve, whereby the position of the earth by day and night will be shown.

Surrounding the aforesaid sleeve 9 is a second sleeve, 71, also provided with an inclined crown-wheel, h. To the said sleeve h are attached the meridian h and the curved arms hf. (See Fi 2.)

To the meridianh is affixed the equatorial section It, and to the curved arms 71; is pivoted the annulus H, representing the line of illumination. The teeth upon the aforesaid crown- By this construction it wheel h mesh with like teeth upon a second crown-wheel, e, borne by a sleeve, 0, arising upward from the case E.

The object of the foregoing mechanism is as follows: It is obvious that the meridian and the curved arms bearing the line of illumination occupy a fixed position relative to the axial inclination of the earth, and also a fixed position relative to the sun. In other words, if the sleeve 7:, carrying said parts. were al lowed to revolve with the sleeve said meridian and line of illumination would only occupy their proper position once in each revolution of the earth around the sun. To avoid this difficulty, I use the crown-wheels h and c, which latter, being fixed, retains said wheel h'lll a relatively fixed position, while at the same time it allows the direction of the inclination of said wheel h, sleeve It, and meridian and curved arms h" to change with that of the earths axis. The aforesaid line of illumination H must at all times remain at right angles to the plane of the suns direct rays, and in order to effect this I-pivot an arm, H, to the end (or north pole) of the axis F. Upon the outer end of this arm is a bifurcated swivel, H", within the bifurcation of which the aforesaid line of illumination rests. Said arm H. is of a length to compensate for the twenty-three and one-half degrees of inclination of the earths axis. The said arms h" are of such length as to allow the line of illumination to be journaled in their extremities in the plane of the earths equator. The effect of this construction is that when the direction of the axial inclination of the earth changes, the aforesaid arm H prevents the line of illumination from tilting at the poles, while the equatorial pivotal points in the curved arms It prevent it from varying at the equator. If thought desirable, there may be attached by braces to the line of illumination a second annulus, representing the line of twilight, as shown in Fig. 4.

Upon the shaft 9 above the top of the case E, is a second gear-wheel, 7a, meshing with a wheel, k, which has its bearing on the sleeve Said wheel has secured to its upper surface a curved rod, 7%, which bears upon its upper extremity a sphere, K, which represents the moon. By this construction it will be seen that as the shaft D revolves and simultaneously with the revolution of the earth upon its axis and around the sun, and with its change of direction of axial inclination) the moon, through the medium of the described mechanism, will be caused to revolve around the earth, and thus demonstrate the phenomena of the rising and setting of the moon, the eclipses, &c.

It will be understood that the various gearwheels throughout the machine are provided with the proper number of teeth required to impart correct relative amounts of motion to the various parts.

Having thus specifically described the various trains of mechanism and their resultant ITO motions, the general operation of the machine is as follows: The arm G is revolved from right to left. As said arm revolves it is lengthened and shortened in the manner described, whereby the earth is made to follow an elliptical path. At the same time the shaft F is gradually revolved, and the axial inclination of the earth thereby changed, the sleeves g and g" revolved, and the motion of the earth upon its axis thereby effected, the wheel 76 revolved, and the revolution of the moon about the earth thereby shown, and, finally, the line of illumination automatically adjusts itself as the occasion requires.

Having thus described my invention, what I claim is 1. In an astronomical instrument, the combination, with the stand A, having revolving cover A and provided with eccentric guide channel A, of the earth-bearing arm 0, provided with lug O, substantially as described, whereby the earth is made to describe an elliptical orbit, as set forth.

2. In an astronomical instrument, the combination, with the revolving shaft D and the shaft F, of the wheel f, pinion f, worm f, and wheel f substantially as described, where by the change in the direction of the axial inclination of the earth is effected, as set forth.

In an astronomical instrument, the com-,

videdwithcrown-wheel g, and sleeve 9 provided with crown-wheel g, substantially as described, whereby the revolution of the earth upon its axis is effected, as set forth.

5. I11 an astronomical instrument, the combination, with the sleeve 5/ and the arms 71", of the sleeve 71 crown-wheel 71 and sleeve e, provided with crown-wheel a, substantially as described, whereby the arms h" are prevented fromrevolving with the sleeve 9 as set forth.

6. In an astronomical instrument, the combination, with the line of illumination H, provided with means for journaling it upon the plane of the ecliptic and the axis F, of the arm H, provided with bifurcated swivel H", substantially as and for the purposes described.

7. In an astronomical instrument, the combination, with shaft provided with means for revolving it, the moon K, and rod if, of the wheels 7; 7t, substantially as described, whereby the moon is revolved about the earth, as set forth.

8. In an astronomical instrument, the combination, with the stand A, provided upon its top with a circular toothed rack, and having a revolving cover, A", the earth-bearing arm 0, having means for reciprocating it, and the revolving shaft D, having bearings in said arm, of an elongated. pinion carried by said shaft D, and adapted to gear with the cogs of the circular toothed rack while the arm 0 is being simultaneously revolved and reciprocated, substantially as and for the purposes set forth.

JOHN DAVIS, \Vi tn esses:

A. O. .ToHNsroN, G. S. JonNs'roN. 

